My only comment would be, if you want reliable replication, use
delta-syncrepl.

Are you saying syncrepl is known to be broken? Or shoddy in general? I find the
whole issue that a "top level" of a tree can disappear, but the tree itself
still works to be troubling. Perhaps BerkeleyDB broken?

I did look at delta-syncrepl, but it never ran very well, and seemed quite over
complicated for marginal gains. As I understood it, syncrepl always sends entire
records, whereas delta-syncrepl can update just the attribute of a record. This
did not sound like it would make any difference. Is my understanding incorrect?

This is what I added to the slapd.conf on master when testing it. Currently, not
on the production servers.